CTDL 167: Nuclear power pollution

The case for nuclear power as a low carbon energy source to replace fossil fuels has been challenged in a new report by Australian academics.
It suggests greenhouse emissions from the mining of uranium – on which nuclear power relies – are on the rise.
Availability of high-grade uranium ore is set to decline with time, it says, making the fuel less environmentally friendly and more costly to extract.

Call me captain obvious (no really, it would be a fun nickname), but don’t we have a few dozen thousand nuclear weapons here and in the former USSR that could be decommissioned and that ore could be used? I’ll admit to not knowing how much Uranium it takes to run a reactor, but I would think there’s probably a fair bit of the stuff in all those bombs we made during the cold war. If you’re using them for powering the world’s energy needs I think leaders would be less tempted to use them for blowing people up (which is largely a good idea).

2 Comments

Ken wrote:

It’s not just that we have warheads to burn, which are actually running out since we the treaty obligations that made them available will be satisfied soon, its that even a massive increase in carbon cost for uranium sourcing and processing is dwarfed by the mining and transportation carbon expenditures for coal. In the US alone we mine and transport billions of tons of coal, removing whole mountains to do so. We transport it long distances. Then we burn it. The resulting release of CO2 from the final stage dwarfs the sourcing and transportation cost, which dwarf those analogous costs for uranium. Its an egregious false accounting and only looks significant if one were to start by assuming a zero emission for nuclear, which is false.

Currently most of the carbon involved in nuclear fuel production in the US is from isotopic purification. This has nothing to do with ore grade since it will be the same regardless of where the yellow cake came from. We will soon move from our 1950’s era diffusion plant to new centrifuge plants with state of the art European centrifuges that take 5% of the power compared to the one in Kentucky. This will drop the carbon cost of nuclear by a degree that will make any rise in mining cost get lost in measurement error.

Serious prospecting for Uranium has only just re-started in earnest of the last five to ten years due to the rise in uranium prices (due to decreased supply of weapons grade uranium). It is unclear that we have come very close to exhausting our known uranium reserves. As Rummy would put it, this is an known unknown.

Thorium is an emerging competitor with uranium as a fuel for nuclear power plants. Current PWR plants can burn fuel designs utilizing thorium with little retrofitting of the reactor core. At least two generation IV reactor designs utilize thorium even more efficiently. This would be truly exciting. Thorium is 4 times more abundant in the crust than uranium, and even though uranium’s chemical properties allow it to become concentrated in large high grade deposits, there are concentrated mineral deposits of thorium that could support the industry comfortably, such as mozerite sands in India and Brazil and the igneous formations in Idaho. There have got to be scores more, no one has seriously prospected for this metal, these were found more by chance. The US government just stored 3200 tons of pure Thorium nitrate in Nevada and thorium is a typical and normally unwanted bi-product of rare earth metal refinement. It is mildly radioactive so it can’t be disposed of and sits in yellow drums with rad waste labels. There is probably enough Thorium to power the planet’s fleet of PWRs for a few years and maybe decades already partially purified and sitting a such refiners of dump sites who may even love to get rid of it. Since it is already mined, this would dramatically cut costs. Since it is used in a LWR breeder cycle, it stays in the reactor between 9 and 14 years, with and estimated 100GW/kg burnup. When it is done, a grand majority of its products decay to background within 500 years. Once the first cooling phase is done, you could put the spent rods in a cask, fill it with concrete and then seal it. Given the short half lives involved, you could sink these to the bottom of the ocean of the bottom of a deep mine and forget about them. By the time the containment is compromised, the contents will be cold a back yard dirt. The only fly in the ointment is that the rods contain U233, which as some point you might want to recover to put in new thorium fuel pellets as a driver for the reaction in second generation fuel, so you may view the spent fuel as too valuable to throw away.

Wow, that’s a lot of info for me to look up. Thanks for the comment and info. Just looking at the reduction in numbers of warheads I had missed how many we’d gotten rid of in the last 10 years. Do you know what the “available powers” is in a warhead? I’m curious to know if the uranium in a warhead would run a reactor for 5 hours, 5 weeks, or 5 years.